Motot Oil Weight

I bought a pre-owned 2000 Ford Ranger from a used car dealer. I changed the oil three times, using good ol’ 10W-30, before reading the owner’s maunual recommendation to use 5W-30. I have no idea whether the previous owner complied with the manual’s recommendation or, like me, used 10W-30.

At this point, should I continue using 10W-30 or 5W-30?

You’ve gotten responses to this already: http://community.cartalk.com/posts/list/2222006.page